Actually, the Heritage feats don't have alignment prereqs...at least not the Draconic, Celestial or Infernal ones, as I recall.
(The ones from the Planar Handbook may differ.)
In addition, if you have the Draconomicon, there are some Draconic feats that are similar to the Reserve feats, doing things like letting you fling electrical orbs instead of using the Electrical breath weapon...
Greatspear is an Exotic weapon- I think you mean longspear, right?
At any rate, if you go for a reach weapon build, I'd still consider burning a feat on a quality reach weapon at some point, be it martial or exotic.
In addition, with a Quiver of Ehlonna (a.k.a. Efficient Quiver), a high-dex caster based on casting rays, orbs and other ranged touch attacks can become a mini-howitzer. Since the other feats for that build are Point-Blank Shot and Precise shot, you'll get full benefit of those feats with your spears, javelins and X-bow bolts in the Quiver...and in this particular case, your Eldritch Blast. (And certain Reserve feats as well.)
I don't know if your group uses the DCv1 at all, but its full of polearms- many updated all the way from AD&D- and polearm feats as well.